1. Field of the Invention
This invention generally relates to packaging processes, and in particular to those processes pertaining to the packing of items having sharp or fragile surfaces. More particularly, this invention relates to the application of cushioning materials to exterior container surfaces. This invention also relates to foamed or non-foamed polymeric materials suitable for use in such processes.
2. Description of the Relevant Art
In a variety of areas, it is necessary to package products in such a manner that sharp protrusions or fragile portions are cushioned. This is particularly necessary in any industry where products are wrapped in air-tight polymeric films.
One of these industries is the food industry, and particularly the meat packing industry. Most meat portions are irregularly shaped and contain bones which protrude at one or more places on the cut. The relatively sharp protrusions can tear and pierce the outer polymeric wrap in which the meat is encased. During storage and shipment from packing plant to warehouse, retailer or user, the cut is handled several times, further increasing the chances of puncture or tearing of the outer wrap. This is particularly possible at the point of contact between the bag and the protruding bone. Vacuum packaging to increase storage life also increases the risk of the outer wrap tearing. In vacuum packaging, the wrap is forced to conform to the contours of the meat during the evacuation process. This can cause stretching and strain over the protruding areas.
Various approaches have been tried to overcome the problems associated with torn or leaking outer wrappers. For example, the outer wrapper material may be strengthened to resist puncture. This would entail modification of the content or thickness uniformly throughout the wrapper which would be expensive and unnecessary in view of the fact that the areas likely to be punctured are relatively limited.
Specialized containers have been proposed such as the one disclosed to U.S. Pat. No. 4,136,205 to Quattlebaum. Such containers or bags are generally reinforced with suitable cloth or strengthening material at points in the bag which roughly correspond to the protrusions. These containers are relatively expensive and require accurate placement of the meat cut within them if they are to function satisfactorily.
Various drawbacks can be found when applying a hot melt material to an exterior surface of a polymeric bag or other outer containers. If the contact temperature were too high, the strength and integrity of the polymeric bag or container would be compromised. Where the application temperature would be low enough so as to keep the container integrity intact, problems with insufficient adhesion would be generally encountered. Aside form the meat packing industry, many other industries involved in packing or shipping products having fragile regions needing additional protection are searching for ways to cushion and protect these regions.
Thus, it is desirable to provide a process for protecting the exterior surfaces of products having sharp protrusions or fragile regions. It would be desirable that this process employ a polymeric material which can be easily and selectively applied to these surfaces without compromising the strength and integrity of a polymeric bag or container, and without harming the product if applied to the product surface itself. It is also desirable to provide a process in which a foamed or non-foamed material can be produced at the use site and dispatched at low temperatures for a variety of packaging and other applications.